Problems with the critical speed model: Can power laws predict running performance better?

Digital art image of a runner with math equations in the background

The critical speed model—also known as critical velocity, CV, or critical power—is a powerful concept for understanding what running speeds are sustainable at a metabolic steady-state and what speeds are not.

Critical speed is not without its detractors, though, and the critical speed model is certainly not without its flaws.

I just posted a huge article on understanding the science of critical speed, critical velocity, and critical power for runners. That article goes in-depth on what critical speed is, how the model works, and how you can use it in your training.

I was originally planning on including the major criticisms of critical speed as a part of that article, but it’s long enough as it is.

So here, separately, is a summary and analysis of the main problems with critical speed (and, by extension, critical power) as a model for endurance performance, plus some rejoinders as to why alternative models, like the power law model of performance, are not always better.

Read more

The science of critical speed, critical velocity (CV), and critical power training for runners

Female athlete running in front of scientific graphic paper

Critical speed is the boundary that separates running speeds that can be sustained at a metabolic steady-state from speeds that cannot. Sometimes called critical velocity or “CV,” critical speed is known in the running world in partly due to its popularization by Tom “Tinman” Schwartz and his proteges, including Drew Hunter.[1]

Critical speed is increasingly becoming the gold standard among physiologists for identifying the limit of what runners would call “high-end aerobic” or “steady-state” running speeds, and is gaining traction as a training tool as well. The critical speed model explains the body’s response to different speeds better than older models based on the lactate threshold.

Among exercise physiologists, critical speed (or a semi-related concept, the maximum lactate steady state, which we’ll also discuss) is rapidly becoming the gold standard for capturing the aerobic fitness of athletes.

Critical speed has its roots in early work in the 1960s, 70s, and 80s, but didn’t really start to emerge as the strongest physiological model for intense exercise until the last 15 years or so.

In this article, we’ll take a detailed look at the critical speed phenomenon, understand how it works on a mathematical and physiological level, see some of the problems and controversies surrounding it, and learn how to apply the concept of critical speed in your own training.

Read more

The Keys to Marathon Training: Modern changes to Renato Canova’s elite marathon training methods

While researching my blog post on Renato Canova’s marathon training book, I came across a lecture that Canova gave at a coaching conference put on by Spanish marathoner and coach Antonio Serrano in 2017. The talk, called The Keys to Marathon Training[1] was held in conjunction with the 2017 Valencia Marathon.

This lecture directly answers one of the questions I had when writing up my analysis of Canova’s book–what’s changed since 1999? From his answers in a 2011 interview, I knew that Canova believed some important things had changed, but that video didn’t go into too much detail. Canova’s talk at this conference goes into much more depth, so I wanted to do a more formal write-up on it.

Read more

Review and summary of Marathon Training - A Scientific Approach by Renato Canova

Photo of the book Marathon Training - A Scientific Approach by Renato Canova and Enrico Arcelli

How do the best marathon runners in the world train? While you might catch a workout or two on Instagram or hear rumors about epic training weeks on message boards, there’s precious little information on the systematic approaches that elite coaches use with top marathon runners–and even less information on the science that backs up these approaches for designing marathon training programs.

One exception to this general rule has been the Italian coach Renato Canova, arguably the greatest living running coach and the topic of several of my previous posts on Running Writings. Canova freely discusses his training philosophy and posts example workouts or even full training schedules for the athletes he has worked with, which include Olympic and World Championships medallists.

In 1999, Canova even co-authored a book on the science of marathon training—however, there’s a bit of a catch: this book was printed through the IAAF (now World Athletics), not a traditional publishing company or printing press. As a result, Canova’s book is extraordinarily rare. I had heard of this book probably a decade ago, but in the intervening years I couldn't find any substantive information on its contents. Until now.

Read more

A scientific guide to treadmill training and workouts for runners

Stylized image of treadmills in a gym

Though many runners treat treadmills as a necessary evil, treadmill access is a must-have if you live anywhere that gets extreme cold or extreme heat and want to train seriously year-round. Being from Minnesota (and having coached many runners in the Midwest), I’ve had plenty of experience modifying workouts and training sessions for the treadmill. 

On top of that, I’ve just wrapped up a biomechanics study as a part of my PhD dissertation that involved 60 runners completing a treadmill run in a motion capture lab, so I have a lot of experience working with biomechanical data from treadmill running. 

When you’re doing treadmill workouts, you can’t always just translate your outdoor workouts 1:1 and expect everything to go well. There are several important physiological, biomechanical, and psychological aspects of treadmill running that differ from outdoor running. 

Moreover, I’ve found that a lot of runners have ideas about treadmill training that aren’t in alignment with the scientific research on treadmill running. So, this article is designed to refute some of these incorrect ideas, and provide some guidance on how to incorporate treadmill running, when necessary, into your own training. 

Just want to know the most important info before you hit the treadmill? Click the link below to go directly to my seven scientifically-supported best practices for treadmill training.

Read more

Advanced versions of strides and accelerations for runners

The homestretch of a track at night

When runners ask online about ways to improve their running form or increase their footspeed, a common response is “add some strides.” It’s assumed or implicit in such a response that everyone knows what strides are and how to do them optimally.

As with many things in training, it’s worth spending some time to dig into what constitutes “doing strides,” and how we might incorporate them into training in a more thoughtful way. 

Read more

Getting the cool-down right

Several years ago I wrote about getting the warm-up right, and I still believe that many runners neglect the warm-up to their own detriment. But after you work out, what about the cooldown (or, less commonly these days, a “warm-down”)? How long, how far, and how fast should a cooldown be? Getting to a place where we can answer these questions is going to require getting a framework in place where we understand why you should cool down in the first place.

Understanding the reasons for doing a cool-down after a workout

Like much of the accumulated lore of running, the common rationales for doing a cool-down at all contain a healthy mix of physiology, bro science, folk wisdom, and true coaching wisdom. Allegedly, the cooldown is supposed to gradually reduce your heart rate, pump “lactic acid” out of your muscles, and condition your legs to running while tired. Failing to cool down is again allegedly supposed to make you feel more sore the next day, and harm your recovery capabilities. Needless to say, each of these rationales has a hefty amount of myth alongside perhaps a kernel of truth.

Instead of trying to consider and analyze each of these claims in turn, I think it’s better to break the question of “why do a cooldown” into smaller parts: who is doing the cooldown, what workout does it follow, and what training goals are we trying to accomplish, both in this workout and in the longer-term training plan.

Read more

How much easier is running on an AlterG? Developing equal-intensity curves for anti-gravity treadmill running

Have you ever run on an AlterG? Once firmly in the realm of space-age gadgetry only available to professional athletes, AlterG anti-gravity treadmills seem to be cropping up everywhere nowadays. College athletic departments, physical therapy offices, and even the occasional high school are purchasing AlterGs for their widely lauded ability to allow runners and other ... Read more

Getting the warm-up right

How do you warm up for a race or workout? If you're like most high school and college runners, your warm-up is probably not too far off from Joe Rubio's humorous characterization of the typical runner's pre-workout routine "10-15 min easy. 4 half-hearted strides. BS a bit. Run the workout" This might be sufficient if ... Read more

Did you know I have a book? Check it out here!